4.4 Matching any two complex impedances - Smith Chart Matching
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4.4.2 Admittance Smith Chart
When it comes to admittance, we may follow a similar procedure. First of all, we normalise
each admittance by diving it by the characteristic admittance of the RF system, which is equal to the
inverse of the characteristic impedance,
⁄
.
Yet again we will indicate the normalised admittances, and their respective conductances and
susceptances with lower case letters and un-normalised ones with upper case letters. For an
admittance we define a normalised equivalent as
To de-normalise our admittance all we need to do is multiply by
. Also note how an admittance
equal to the characteristic admittance of the system, has a normalised value of 1.
Next we consider lines of constant normalised conductance (Figure 4.4-7) and lines of
constant normalised susceptance (Figure 4.4-8). And we bend them in such a way as to fit in the
unity radius polar plot of the reflection coefficient as shown in Figure 4.4-9.
Figure 4.4-7 Constant Normalised conductance circles
Figure 4.4-8
Constant normalised susceptance circles
Conquer Radio Frequency
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